This application requests funding to support the 2015 International Molecular and Functional Pulmonary Imaging Workshop, a three-day meeting scheduled for November 12-14, 2015. The proposed workshop will be the fifth of its kind held at the University of Pennsylvania. The funds will be used to cover travel and lodging expenses of expert and trainee speakers. They will also support the webcasting and publication of the entire proceeds of the workshop. As we have done in the past, we plan to broadcast the workshop live over the web to be freely accessed by interested parties who cannot physically attend. Pulmonary diseases are a massive and growing cause of global morbidity and mortality, and the field of imaging has become an important source of innovation in diagnosing and treating these pathologies. Pulmonary imaging now comprises a litany of techniques for functional, structural, and molecular assessment being rapidly developed and refined by investigators in numerous fields including biology, medicine, physics, engineering, and chemistry. In light of the diverse and fast-changing nature of the field, regularly holding a workshop that brings together pulmonary imaging scientists and clinicians for the rigorous exchange of ideas is imperative. To our knowledge, our workshops are the only venues that include each major component of the field in a space solely dedicated to pulmonary imaging. The specific aims of the proposed workshop are as follows: (1) inform the pulmonary imaging community about the latest developments in structural and functional lung imaging; (2) explore fundamental cellular and molecular mechanisms underlying serious lung diseases and how they can be imaged with cutting-edge techniques; (3) examine the use of pulmonary imaging for assessing therapeutic response and the challenges inherent to this objective; (4) broadcast the entire proceedings live over the web to be freely accessed by non- attendees and allow this audience to participate in workshop discussions in real time. Of these components, two are novel to this iteration of the pulmonary imaging workshop. While in our 2013 workshop we introduced molecular lung imaging to the proceedings to complement our traditional focus on functional and structural approaches, the proposed 2015 meeting will much more thoroughly focus on molecular techniques. It will include discussion of the whole range of molecular approaches, including PET and SPECT, hyperpolarized 13C MR, and optical imaging as well as talks on lung biology designed to spur the development of novel molecular probes. The explicit focus on imaging techniques to assess therapeutic response is also a new aspect of the workshop. The development of successful treatments for lung diseases has been stunted by a lack of imaging approaches for the effective measurement of response. A greater emphasis on this issue reflects the urgency of developing better imaging techniques for therapeutic assessment.